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Diffstat (limited to 'ast/erfa/atioq.c')
| -rw-r--r-- | ast/erfa/atioq.c | 243 |
1 files changed, 0 insertions, 243 deletions
diff --git a/ast/erfa/atioq.c b/ast/erfa/atioq.c deleted file mode 100644 index d8a1f7b..0000000 --- a/ast/erfa/atioq.c +++ /dev/null @@ -1,243 +0,0 @@ -#include "erfa.h" - -void eraAtioq(double ri, double di, eraASTROM *astrom, - double *aob, double *zob, - double *hob, double *dob, double *rob) -/* -** - - - - - - - - - -** e r a A t i o q -** - - - - - - - - - -** -** Quick CIRS to observed place transformation. -** -** Use of this function is appropriate when efficiency is important and -** where many star positions are all to be transformed for one date. -** The star-independent astrometry parameters can be obtained by -** calling eraApio[13] or eraApco[13]. -** -** Given: -** ri double CIRS right ascension -** di double CIRS declination -** astrom eraASTROM* star-independent astrometry parameters: -** pmt double PM time interval (SSB, Julian years) -** eb double[3] SSB to observer (vector, au) -** eh double[3] Sun to observer (unit vector) -** em double distance from Sun to observer (au) -** v double[3] barycentric observer velocity (vector, c) -** bm1 double sqrt(1-|v|^2): reciprocal of Lorenz factor -** bpn double[3][3] bias-precession-nutation matrix -** along double longitude + s' (radians) -** xpl double polar motion xp wrt local meridian (radians) -** ypl double polar motion yp wrt local meridian (radians) -** sphi double sine of geodetic latitude -** cphi double cosine of geodetic latitude -** diurab double magnitude of diurnal aberration vector -** eral double "local" Earth rotation angle (radians) -** refa double refraction constant A (radians) -** refb double refraction constant B (radians) -** -** Returned: -** aob double* observed azimuth (radians: N=0,E=90) -** zob double* observed zenith distance (radians) -** hob double* observed hour angle (radians) -** dob double* observed declination (radians) -** rob double* observed right ascension (CIO-based, radians) -** -** Notes: -** -** 1) This function returns zenith distance rather than altitude in -** order to reflect the fact that no allowance is made for -** depression of the horizon. -** -** 2) The accuracy of the result is limited by the corrections for -** refraction, which use a simple A*tan(z) + B*tan^3(z) model. -** Providing the meteorological parameters are known accurately and -** there are no gross local effects, the predicted observed -** coordinates should be within 0.05 arcsec (optical) or 1 arcsec -** (radio) for a zenith distance of less than 70 degrees, better -** than 30 arcsec (optical or radio) at 85 degrees and better -** than 20 arcmin (optical) or 30 arcmin (radio) at the horizon. -** -** Without refraction, the complementary functions eraAtioq and -** eraAtoiq are self-consistent to better than 1 microarcsecond all -** over the celestial sphere. With refraction included, consistency -** falls off at high zenith distances, but is still better than -** 0.05 arcsec at 85 degrees. -** -** 3) It is advisable to take great care with units, as even unlikely -** values of the input parameters are accepted and processed in -** accordance with the models used. -** -** 4) The CIRS RA,Dec is obtained from a star catalog mean place by -** allowing for space motion, parallax, the Sun's gravitational lens -** effect, annual aberration and precession-nutation. For star -** positions in the ICRS, these effects can be applied by means of -** the eraAtci13 (etc.) functions. Starting from classical "mean -** place" systems, additional transformations will be needed first. -** -** 5) "Observed" Az,El means the position that would be seen by a -** perfect geodetically aligned theodolite. This is obtained from -** the CIRS RA,Dec by allowing for Earth orientation and diurnal -** aberration, rotating from equator to horizon coordinates, and -** then adjusting for refraction. The HA,Dec is obtained by -** rotating back into equatorial coordinates, and is the position -** that would be seen by a perfect equatorial with its polar axis -** aligned to the Earth's axis of rotation. Finally, the RA is -** obtained by subtracting the HA from the local ERA. -** -** 6) The star-independent CIRS-to-observed-place parameters in ASTROM -** may be computed with eraApio[13] or eraApco[13]. If nothing has -** changed significantly except the time, eraAper[13] may be used to -** perform the requisite adjustment to the astrom structure. -** -** Called: -** eraS2c spherical coordinates to unit vector -** eraC2s p-vector to spherical -** eraAnp normalize angle into range 0 to 2pi -** -** Copyright (C) 2013-2016, NumFOCUS Foundation. -** Derived, with permission, from the SOFA library. See notes at end of file. -*/ -{ -/* Minimum cos(alt) and sin(alt) for refraction purposes */ - const double CELMIN = 1e-6; - const double SELMIN = 0.05; - - double v[3], x, y, z, xhd, yhd, zhd, f, xhdt, yhdt, zhdt, - xaet, yaet, zaet, azobs, r, tz, w, del, cosdel, - xaeo, yaeo, zaeo, zdobs, hmobs, dcobs, raobs; - - -/* CIRS RA,Dec to Cartesian -HA,Dec. */ - eraS2c(ri-astrom->eral, di, v); - x = v[0]; - y = v[1]; - z = v[2]; - -/* Polar motion. */ - xhd = x + astrom->xpl*z; - yhd = y - astrom->ypl*z; - zhd = z - astrom->xpl*x + astrom->ypl*y; - -/* Diurnal aberration. */ - f = ( 1.0 - astrom->diurab*yhd ); - xhdt = f * xhd; - yhdt = f * ( yhd + astrom->diurab ); - zhdt = f * zhd; - -/* Cartesian -HA,Dec to Cartesian Az,El (S=0,E=90). */ - xaet = astrom->sphi*xhdt - astrom->cphi*zhdt; - yaet = yhdt; - zaet = astrom->cphi*xhdt + astrom->sphi*zhdt; - -/* Azimuth (N=0,E=90). */ - azobs = ( xaet != 0.0 || yaet != 0.0 ) ? atan2(yaet,-xaet) : 0.0; - -/* ---------- */ -/* Refraction */ -/* ---------- */ - -/* Cosine and sine of altitude, with precautions. */ - r = sqrt(xaet*xaet + yaet*yaet); - r = r > CELMIN ? r : CELMIN; - z = zaet > SELMIN ? zaet : SELMIN; - -/* A*tan(z)+B*tan^3(z) model, with Newton-Raphson correction. */ - tz = r/z; - w = astrom->refb*tz*tz; - del = ( astrom->refa + w ) * tz / - ( 1.0 + ( astrom->refa + 3.0*w ) / ( z*z ) ); - -/* Apply the change, giving observed vector. */ - cosdel = 1.0 - del*del/2.0; - f = cosdel - del*z/r; - xaeo = xaet*f; - yaeo = yaet*f; - zaeo = cosdel*zaet + del*r; - -/* Observed ZD. */ - zdobs = atan2(sqrt(xaeo*xaeo+yaeo*yaeo), zaeo); - -/* Az/El vector to HA,Dec vector (both right-handed). */ - v[0] = astrom->sphi*xaeo + astrom->cphi*zaeo; - v[1] = yaeo; - v[2] = - astrom->cphi*xaeo + astrom->sphi*zaeo; - -/* To spherical -HA,Dec. */ - eraC2s ( v, &hmobs, &dcobs ); - -/* Right ascension (with respect to CIO). */ - raobs = astrom->eral + hmobs; - -/* Return the results. */ - *aob = eraAnp(azobs); - *zob = zdobs; - *hob = -hmobs; - *dob = dcobs; - *rob = eraAnp(raobs); - -/* Finished. */ - -} -/*---------------------------------------------------------------------- -** -** -** Copyright (C) 2013-2016, NumFOCUS Foundation. -** All rights reserved. -** -** This library is derived, with permission, from the International -** Astronomical Union's "Standards of Fundamental Astronomy" library, -** available from http://www.iausofa.org. -** -** The ERFA version is intended to retain identical functionality to -** the SOFA library, but made distinct through different function and -** file names, as set out in the SOFA license conditions. The SOFA -** original has a role as a reference standard for the IAU and IERS, -** and consequently redistribution is permitted only in its unaltered -** state. The ERFA version is not subject to this restriction and -** therefore can be included in distributions which do not support the -** concept of "read only" software. -** -** Although the intent is to replicate the SOFA API (other than -** replacement of prefix names) and results (with the exception of -** bugs; any that are discovered will be fixed), SOFA is not -** responsible for any errors found in this version of the library. -** -** If you wish to acknowledge the SOFA heritage, please acknowledge -** that you are using a library derived from SOFA, rather than SOFA -** itself. -** -** -** TERMS AND CONDITIONS -** -** Redistribution and use in source and binary forms, with or without -** modification, are permitted provided that the following conditions -** are met: -** -** 1 Redistributions of source code must retain the above copyright -** notice, this list of conditions and the following disclaimer. -** -** 2 Redistributions in binary form must reproduce the above copyright -** notice, this list of conditions and the following disclaimer in -** the documentation and/or other materials provided with the -** distribution. -** -** 3 Neither the name of the Standards Of Fundamental Astronomy Board, -** the International Astronomical Union nor the names of its -** contributors may be used to endorse or promote products derived -** from this software without specific prior written permission. -** -** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS -** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT -** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS -** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE -** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, -** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, -** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; -** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER -** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT -** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN -** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE -** POSSIBILITY OF SUCH DAMAGE. -** -*/ |